Glossary of Key Terms
Glossary of Key Terms
| Term | Definition |
| Astable Multivibrator | A multivibrator circuit that automatically switches between two quasi-stable states continuously without any external pulse. It is also called a Free-running Multivibrator. |
| Bidirectional Sampling Gate | A type of sampling gate that can transmit signals of both positive and negative polarities. |
| Bidirectional Signal | A signal that alters in both positive and negative directions, crossing the zero point. Example: Sinusoidal signal. |
| Bistable Multivibrator | A multivibrator with two stable states. It requires two trigger pulses to change states and is also known as a Flip-flop. |
| Blocking Oscillator | A relaxation oscillator that uses regenerative feedback (via a pulse transformer) to generate narrow pulses, blocking the feedback for a predetermined time after each cycle. |
| Bootstrap Sweep Generator | A time base generator where the output is fed back to the input to achieve a constant charging current, resulting in a very linear output voltage ramp. |
| Commutating Capacitors | Also known as Speed-up Capacitors, these are used in Bistable Multivibrators to reduce the transition time for conduction to transfer from one transistor to the other. |
| Cut-off | The “OFF” state of a transistor switch, where the base current is zero (ideally), resulting in zero collector current and an output voltage equal to the supply voltage (VCC). |
| Displacement Error (ed) | A measure of sweep linearity defined as the maximum difference between the actual sweep voltage and an ideal linear sweep that passes through the beginning and end points of the actual sweep. |
| Duty cycle | The ratio of the pulse width to the period of a waveform. |
| Electronic Switch | A switch, such as a transistor, that uses a solid-state device for operation, characterized by high operating speed, absence of sparking, and no moving parts. |
| Fall time (tf) | The time taken for a signal to fall from 90% to 10% of its maximum amplitude. For a transistor switch, it’s the time for the collector current to fall from 90% to 10% of its maximum value. |
| Hysteresis | A phenomenon in circuits like the Schmitt Trigger where the output value depends on both the present and past values of the input, characterized by different upper and lower switching thresholds. |
| Miller Sweep Generator | An integrator circuit, often used for horizontal deflection, that produces a sweep waveform. It typically uses an amplifier configuration with a timing capacitor providing feedback. |
| Monostable Multivibrator | A multivibrator with one stable state and one quasi-stable state. It requires an external trigger pulse to transition to the quasi-stable state, earning it the name “One-shot Multivibrator.” |
| Multivibrator | A two-stage resistance-coupled amplifier with positive feedback from the output of one stage to the input of the other, used to generate non-sinusoidal waves. |
| Overshoot | A condition where the leading edge of a waveform exceeds its normal maximum value. |
| Peak Voltage (VP) | In a UJT, the voltage point at which the emitter diode becomes forward biased and the device turns ON, marking the end of the cut-off region. |
| Pedestal | An unwanted DC offset in the output of a sampling gate, which is the output voltage level present due to the control signal even when the input signal is zero. |
| Pulse Signal | A unidirectional, non-sinusoidal signal formed by a rapid transient change from a baseline value to a different level, which returns to the baseline after a certain time period. |
| Pulse transformer | A wide-band transformer designed to couple a source of rectangular electrical pulses to a load while preserving the pulse shape. |
| Pulse width | The length or duration of a pulse. In a switching context, it is the time duration of the output pulse measured between the 50% levels of the rising and falling waveform. |
| Relay | An electromechanical switch that is partially mechanical and partially electrical, using an energized solenoid to make or break a contact. |
| Relaxation Oscillator | An oscillator that uses regenerative feedback to generate a non-sinusoidal output, typically where a timing interval is set by the charging and discharging of a capacitor. |
| Retrace | Also known as Fly back, it is the process where the beam in a display tube returns from the end of its sweep (e.g., right side) back to the starting point (left side). |
| Ringing | Damped oscillations that follow an overshoot or undershoot in a pulse signal. These are unwanted disturbances with decreasing amplitude and frequency. |
| Rise time (tr) | The time it takes for a signal to rise from 10% to 90% of its maximum amplitude. |
| Sampling Gate | A circuit (also called a linear or transmission gate) that transmits an input signal to its output only during a specific time interval selected by a control signal. |
| Saturation | The “ON” state of a transistor switch, where the maximum collector current flows and the collector-emitter voltage drops to a very low value (ideally zero). |
| Schmitt Trigger | An emitter-coupled binary circuit that exhibits hysteresis, converting an analog signal into a digital signal by comparing the input against two distinct voltage levels: an Upper Trigger Point (UTP) and a Lower Trigger Point (LTP). |
| Signal | A representation that carries information and indicates the condition of a circuit. Its graphical form provides details on parameters like voltage, frequency, and time period. |
| Slope or Sweep Speed Error (es) | A measure of sweep linearity defined as the difference in the slope at the beginning and end of the sweep, relative to the initial slope. |
| Storage time (ts) | The time interval between the trailing edge of an input pulse and the point where the output has fallen to 90% of its maximum value. |
| Sweep Voltage | A voltage that varies linearly with time, used to deflect the beam horizontally across the screen of a display like an oscilloscope. |
| Synchronization | The process of making two or more waveform generators arrive at a reference point in their cycle at the exact same time. |
| Time Base Generator | An electronic circuit that generates an output voltage or current waveform where a portion varies linearly with time. It is also known as a sweep circuit. |
| Trace | The deflection of a beam across a screen, typically from left to right, caused by a linearly increasing sweep voltage. |
| Transmission Error (et) | The deviation of an output sweep signal from the input sweep signal when it passes through a high-pass circuit. |
| Turn-off time (TOFF) | The sum of storage time (ts) and fall time (tf) in a transistor switch. |
| Turn-on time (TON) | The sum of time delay (td) and rise time (tr) in a transistor switch. |
| Undershoot | A condition where the trailing edge of a waveform exceeds its normal minimum (or baseline) value. |
| Unidirectional Sampling Gate | A type of sampling gate that can pass only positive or only negative going pulses. |
| Unidirectional Signal | A signal that flows in only one direction, either positive or negative. Example: Pulse signal. |
| Unijunction Transistor (UJT) | A three-terminal transistor with one emitter and two bases, containing a single PN junction and known for its negative resistance characteristic. |
| Valley Voltage (VV) | In a UJT, the voltage point that marks the end of the negative resistance region, after which the voltage begins to increase again with increasing current. |